Abstract: In order to provide a light transmitting space to reinforce an intensity of a light tunnel in a DLP projection system, and increase an heat-resistance, provided is a light tunnel of a DLP projection system including a plurality of reflection panels provided in an anteroposterior direction; a holder where the reflection panel is placed; a first supporting member supporting an end of the reflection panel; and a second supporting member supporting a body of the reflection panel.

Abstract: Disclosed is a heterodyne receiver for low noise and image frequency repression, comprising: a low noise amplifier for receiving an input signal from an antenna and amplifying the signal while reducing a noise figure of the input signal; and a frequency converter for receiving both the input signal outputted from the low noise amplifier and a local oscillation signal, filtering the signals to repress gain of the input signal at an image frequency band and increase gain of the input signal at a signal frequency band, and converting the frequency of the signals to the intermediate frequency band.